1. Field of the Invention
The present invention relates to a cleaning apparatus and cleaning method for immersion light exposure, for cleaning a substrate, such as a semiconductor wafer, before and/or after immersion light exposure arranged to subject a resist film formed on the surface of the substrate to a light exposure process through a liquid. The present invention further relates to a control apparatus and storage medium for controlling a cleaning apparatus for immersion light exposure.
2. Description of the Related Art
In the process of manufacturing semiconductor devices, photolithography techniques are used for forming circuit patterns on target substrates, such as semiconductor wafers (which will be simply referred to as “wafer”, hereinafter). Where a circuit pattern is formed by use of photolithography, the process steps are performed, as follows. Specifically, a resist liquid is first applied to a wafer to form a resist film. Then, the resist film is irradiated with light to perform light exposure on the resist film in accordance with the circuit pattern. Then, the resist film is subjected to a developing process. Such photolithography techniques are performed in a system comprising a coating/developing apparatus including a plurality of processing units integrated therein for performing a series of processes, such as resist coating and development after light exposure, as well as a light exposure apparatus connected to the coating/developing apparatus.
In recent years, the integration degree of semiconductor devices becomes increasingly higher to improve the operation speed and so forth. Accordingly, photolithography techniques are required to increase the miniaturization level of circuit patterns formed on wafers. As a photolithography technique for realizing a high resolution of a 45-nm node level, there has been proposed the following immersion light exposure (for example, see U.S. Patent Application Publication No. US 2006/0231206 A1). In this immersion light exposure, a light exposure liquid, such as purified water, having a refractive index higher than air is supplied between the wafer and light exposure projection lens. The wavelength of light radiated from the projection lens is shortened by means of the refractive index of the light exposure liquid, so that the line width obtained by the light exposure is decreased.
Since the immersion light exposure is a technique for performing light exposure through a liquid, wafers to be loaded into the light exposure apparatus should be cleaned more than ever. Further, part of the liquid deposited on wafers during the immersion light exposure may affect subsequent processes. Accordingly, in the case of the immersion light exposure, cleaning is performed on wafers before and/or after the light exposure.
Each of the cleaning processes prior to and subsequent to the light exposure is arranged as a rinsing process using purified water, in general. Since cleaning characteristics vary depending on the type of films formed on wafers, it is necessary to select optimum process conditions and to change hardware conditions, when the type of films is changed. Conventionally, adjustments for the selection and change described above need to be manually performed, thereby taking a long time and lowering the throughput. Further, where adjustments of conditions are manually performed, the process may be insufficiently optimized.